This invention relates to an apparatus for the automated application of spacer material to a substrate such as a glass lite for the manufacture of double-glazed or insulated windows.
Double-glazed or other sandwich type insulated windows are made by applying a spacer material to the periphery of a first glass lite and then applying a second glass lite over the spacer. A desiccant in the spacer serves to absorb any moisture in the trapped air. In order for a window to maintain its integrity, the seal between the glass lites must prevent any further moist air from entering the insulating space. The seal is established by the spacer which is adhesive on opposite edges, and later by a further application of sealant.
The spacer serves to maintain the separation between the glass lites in which the insulating air space is trapped. The spacer generally includes materials such as butyl polymers, silicones, polyvinyl polymers as well as strip metal and other materials. Commonly a strip of flexible insulating material of a cellular or solid structure, such as butyl rubber or silicone foam, is used which includes an impregnated desiccant, a polyester, e.g. MYLAR(trademark), vapour barrier, and pressure sensitive adhesive on opposite edges for sealing to the glass. These spacer materials have an elastic memory and therefore stresses such as being wound around the delivery spool, or bent around curves or corners stretch the spacer unevenly resulting in the spacer trying to return to its natural position after it has been applied.
At present, most double glazed windows are formed by manually applying a length of spacer material about the periphery of the glass. Various types of manual tools are known for this purpose, requiring the operator to move the tool along the sides and ends of the glass lite while feeding a length of the strip or spacer material through or around the tool.
Typical of the arrangements known in the prior art is the device shown in U.S. Pat. No. 4,756,789, issued to Kolff, Jul. 12, 1988. The device provides a plurality of rollers between which is fed spacer material. A guide is provided on this body of the applicator for evenly measuring the spacing around the periphery of the substrate as the spacer is applied. Although a useful arrangement for limited production, this apparatus would be ineffective in an environment where high volume production is required.
As the insulated window industry has developed and improved, consumer tolerance for irregularities in window construction has diminished. The flexible spacer materials bend poorly around corners causing a visible bulge in the interior of the window. Commonly the practice for forming corners is to lift the applicator tool, bend the spacer material, replace the applicator tool and continue to apply spacer. In addition to forming a poor rounded corner, this practice also risks forming an incomplete seal with the glass in the corner areas where the tool is lifted and the adhesive is not pressed against the substrate by the tool. As discussed above, a complete seal is necessary to forming an insulating window. If the seal is broken or incomplete much of the insulating capacity of the window is lost and the glass becomes obscured by condensation.
Gradually the industry has turned to automation in insulated window production in order to increase the speed of production and uniformity of the product, and to reduce production costs. Briefly, the line process for automated or semi-automated window assembly includes a number of station steps. First the glass is washed; it is then fed through an aligning process to the spacer applicator; spacer is applied to the periphery of the glass; a glass lite with spacer applied is aligned with a second clean lite for sandwich assembly; the assembly is then advanced through a pressing roller; the edges are sealed; and the unit is placed in a frame. In an automated process it is important to limit the time in each station because all units advance at the rate of the slowest station. Once each station is occupied, a complete unit is produced from the line, for example, every 20 seconds, or a period equivalent to the duration of the longest station.
An apparatus for a partially automated system which has been proposed in the art for applying an adhesive spacer material to a substrate is disclosed in Lisec, U.S. Pat. No. 4,769,105, issued Sep. 6, 1988. The Lisec apparatus provides a spacer application head which is movable vertically on a carriage member. The glass to which the spacer is applied is movable on a pair of cooperating conveyors in a horizontal direction. In operation the head travels up one end of the glass, the glass is advanced while the head continues to apply spacer, the head travels down the other end, and the glass is returned in the horizontal direction to apply spacer to the fourth side. Thus the head travels the complete periphery of the glass and the operation finishes with the glass in its original starting position. This movement of the glass forward and back is time consuming. At each corner the feed of spacer material is held by a single gripper and the head is rotated. As a result the spacer material is bent, but no means is provided to ensure placement of the corner nor to ensure a good seal in the corner area. Although this patent recognizes the need for sharp corners, those formed by this apparatus still bulge, as is found with the hand applicator. Further, the Lisec device subjects the spacer material to significant stresses of bending and twisting which will deform the spacer making a square, even application impossible. The arrangement is likely more efficient than a hand-held apparatus. However, there is still a need for an apparatus to automatically apply spacer to a glass lite in window assembly with greater efficiency, and in particular to form better corners.
With the present invention, applicant has developed a method and apparatus for automated application of spacer material to substrates, especially glass. More particularly, the method and apparatus of this present invention are intended to automatically apply spacer material to glass lite assemblies suitable for in-line production.
Advantageously, the present method and apparatus provide the mechanism and steps necessary to produce tight accurate corners, including a punch for notching the spacer material in the corner area, and a cooperating pair of lead and lag grippers for forming accurate fold placement.
Furthermore, the present method and apparatus according to the present invention permit the fabrication of a high volume of insulated glass assemblies with a low level of manual intervention and skill required to operate the apparatus. As a result, an improved product is produced at greater cost efficiency with less safety risk to operators.
One object of the present invention is to provide an efficient automated process and apparatus for applying adhesive strip spacer material to a substrate.
A further object of the present invention is to provide an apparatus and process for applying the spacer material around a corner ensuring a good seal to the substrate in the corner area and placing a tight corner in a predetermined location without excess bulging material.
A further object of the present invention is to provide an apparatus and process for applying spacer material to a substrate in a quick and time efficient manner.
A further object of the present invention is to provide an apparatus and process for applying spacer material to a substrate within small tolerances for more accurate placement and good sealing contact with the substrate.
A preferred embodiment of the present invention advantageously comprises an apparatus for applying adhesive spacer material to a substrate, comprising:
a support means for supporting the substrate;
a beam oriented transversely to the support means;
at least one travelling applicator head for applying spacer material to the substrate supported on the beam spaced from the substrate;
at least one feed reel for supplying spacer material to the at least one travelling applicator head;
means for advancing the at least one travelling applicator head relative to the substrate; wherein the at least one applicator head includes:
drive means for providing reciprocal movement of the at least one applicator head on the beam
a central housing secured to the drive means about which the at least one applicator head is rotatable;
a lead gripper and a lag gripper pivotally interconnected about the central housing defining an application channel for receiving the spacer material and applying it to the substrate.
A further preferred embodiment additionally comprises a stationary applicator head for applying a length of spacer material while the substrate is advanced relative to the stationary head and a feed reel for supplying spacer material to the stationary applicator head.
A preferred method according to the present invention comprises a method of applying an adhesive spacer material to the perimeter of a substrate, the substrate having a first and a second lateral side and a first and a second transverse side, in the assembly of insulated windows, comprising the steps of:
a. initializing applicator means in a home position;
b. conveying a substrate to an initial home position;
c. advancing the applicator means transversely across the substrate applying spacer material to a first transverse side of the substrate;
d. forming a corner with the spacer material, comprising
gripping a portion of the applied spacer material while simultaneously rotating a leading portion of the applicator means to fold the spacer material;
gripping an adjacent portion of spacer material at a prescribed angle to the gripped applied spacer to place the folded spacer material precisely on an adjacent side of the substrate;
releasing the gripped spacer material; and
rotating a trailing portion of the applicator means into alignment with the leading portion of the applicator means;
e. advancing the substrate relative to the applicator means while applying spacer material to a lateral side of the substrate;
f. optionally repeating steps c, and/or d, and/or e sequentially or simultaneously to apply spacer material to each lateral and transverse side;
g. cutting off the length of spacer applied by the applicator means; and
h. reconfiguring the applicator means for the next substrate.
In a further embodiment of the invention, there is provided an apparatus for applying adhesive spacer to a substrate, in the production of insulated windows, comprising;
a first applicator head for applying said adhesive spacer to said substrate;
support means for supporting the applicator head a distance from a surface of the substrate;
means for advancing the substrate relative to the applicator head;
feed means for feeding the spacer material at a controllable speed to the applicator head; and
an applicator channel for guiding and positioning the spacer on the substrate;
said applicator channel including a co-operative pair of belts for positioning the spacer at a rate corresponding to said controllable speed;
a pressure belt for pressing on the spacer to provide sealing contact between the spacer and the substrate.
Preferably, the applicator channel comprises two pivotally interconnected sections, comprising a lead gripper and a lag gripper, adapted to apply spacer in an aligned configuration and to fold spacer between them at corners.
In a preferred embodiment, the applicator channel has a variable width for immobilizing spacer within the channel.
In a preferred embodiment, the lead gripper and lag gripper have an independently variable width for immobilizing spacer within the channel.
A preferred embodiment further includes means between the lead gripper and the lag gripper.
The cutter means can be any type of cutter means using one or more blades and may be of varying configuration.
The cutter means may be provided preferably comprising reciprocating knives for simultaneously impinging on opposite sides of the spacer during cutting action.
The applicator head preferably includes a servo motor associated with the advancing belts for controlling the advance of spacer in cooperation with the rate of advance of the substrate relative to the applicator head.
In addition, the feed means includes an independent drive for metering spacer in cooperation with the rate of spacer application.
Preferably, the feed means further includes responsive means for regulating the independent drive for metering spacer in response to the rate of spacer application.
In a preferred embodiment, the independent drive means comprises a motor and variable gearing mechanism.
In a further embodiment, the responsive means comprises a linear displacement variable transducer for measuring a varying length of spacer paid out for the applicator head.
Preferably, pressure belt includes an internal support rail for providing a relatively flat surface over which to apply pressure.
In a preferred embodiment, a variable degree of pressure can be applied by the pressure belt.
The applicator head may include means for advancing in a first direction relative to the substrate and for advancing in a second direction normal to the first direction relative to the substrate.
The first means for advancing the substrate may comprise a conveyor for advancing the substrate relative to the applicator head, and with the second means for advancing comprising a drive means on a beam transverse to the conveyor which supports the at least one applicator head for advancing it relative to the substrate.
An additional applicator head adapted to cooperate with the conveyor may be provided to advance in a single direction relative to the substrate.
The conveyor preferably comprises an infeed conveyor, an outfeed conveyor and a transfer means at an application position between them for advancing the substrate relative to the applicator heads.
The transfer means preferably comprises a free roller at the application position.
In a further preferred embodiment, the present invention comprises an apparatus for applying spacer to a substrate having an application surface, edges and corners, comprising:
means for supporting a substrate;
at least one applicator head for applying spacer on the substrate;
support means for supporting the at least one applicator head a distance from the surface of the substrate;
means for advancing a substrate relative to the at least one applicator head;
feed means for metering spacer to the at least one applicator head;
wherein the at least one applicator head includes an applicator channel for guiding and applying spacer on the substrate, including:
a cooperating pair of advancing belts for applying spacer at a rate corresponding precisely to the rate of advance; and
a pressure belt for impinging on spacer to provide sealing contact between spacer and the substrate.
Preferably, the apparatus includes a means for slitting, cutting or notching the strip, preferably from the exterior face of the strip to partway into the interior body of the strip, by means of a reciprocating cutter. An anvil is positionable between the strip and the substrate where the cutter contacts the strip and elevates the strip off the glass at that point. The method of the present invention preferably includes the step of cutting into the strip at the corners thereof in the manner described above.
The present invention has numerous advantages over manual or other types of spacer element application to substrates. Primarily, the apparatus provides an improved product having tight sealed corners. The present invention also provides an apparatus which can be adapted for in-line production, thus eliminating slow-downs and stockpiling of materials. Speed in production is gained through the use of more than one applicator head, and in the use of the conveyor to advance the glass during application so that the glass with spacer leaves the applicator station from an advanced position in the production line. Still further, the present invention provides an economical apparatus which has a minimal number of movements and consequently, is simpler to construct and operate.
Having thus generally described the invention, reference will now be made to the accompanying drawings illustrating preferred embodiments in which like numerals are used to designate like elements.